Flexible elongate member having one or more electrical contacts

ABSTRACT

A flexible elongate member such as a pressure guide wire ( 1000 ) includes an electrical device such as a pressure sensor ( 1002 ). The pressure sensor ( 1002 ) is electrically connected to conductive bands ( 304 ), ( 306 ) and ( 308 ) located on electrical connector ( 300 ). The electrical connector is attached to core wire ( 602 ) and shaft or hypotube ( 704 ). The use of electrical connector ( 300 ) helps minimize the assembly time of pressure guide wire ( 1000 ), as well as minimize some of the assembly problems associated with prior art designs such as pressure guide wire ( 100 ).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending application Ser. No.09/789,281 entitled “Flexible Elongate Member Having One or MoreElectrical Contacts,” filed on Feb. 20, 2001, allowed, which is acontinuation of application Ser. No. 09/261,935, entitled “FlexibleElongate Member Having One or More Electrical Contacts,” filed on Mar.3, 1999, issued as U.S. Pat. No. 6,210,339, the disclosures of which areexpressly incorporated by reference.

FIELD OF THE INVENTION

This invention relates in general to the field of medical devices, moreparticularly, this invention relates to a flexible elongate member suchas a medical guide wire or catheter having one or more electricalcontacts.

BACKGROUND OF THE INVENTION

Flexible elongate member used in medical applications such as guidewires, catheters, etc., which have electrical devices (e.g., pressuresensors, ultrasound transducers, pressure flow measurement devices,etc.) need to have one or more electrical contacts typically close tothe proximal end of the member. The electrical contacts allow for theelectrical interconnection of the electrical device found on theflexible elongate member, for example, a pressure sensor, to an externalmonitoring apparatus.

Currently there is some difficulty in manufacturing small electricalcontacts on flexible elongate members such as guide wires having adiameter in the order of 0.018 inch or less. In FIG. 1 there is shown aprior art guide wire 100 having an electrical device in the form of apressure sensor 110 located in proximity to the distal end of the guidewire 100. Pressure guide wire 100 includes a plurality of electricalcontacts 104 separated by insulator bands (spacers) 116 which help forma cylindrical connector located close to the proximal extremity 102 ofthe pressure guide wire 100. These electrical contacts 104 areelectrically interconnected to pressure sensor 110 and allow for theconnection of the pressure sensor to an external monitoring apparatus.

The pressure guide wire 100 further includes a shaft also referred to asa hypotube 106 typically formed of stainless steel, a flexible coilmember 108 located on one side of the pressure sensor 110, a radiopaquecoil 112 located on the other side of pressure sensor 110, and a tip114. The pressure sensor 110 is electrically interconnected to contacts104 via a plurality of electrical conductors (not shown), which runthrough the inside of the flexible coil 108 and shaft 106.

The cylindrical guide wire connector formed by contacts 104 isinterconnected to a female connector 200 shown in FIG. 2. The proximalend 102 of pressure wire 100 is inserted in to the nose section 206 ofconnector 200 such that contacts 104 become electrical coupled tocorresponding contacts located inside of the swivel head 204. The otherend of the connector 200 includes a pin plug 202, which interconnects toan appropriate monitoring apparatus, in this case a pressure monitor(not shown). In use, the distal end of pressure wire 100 is insertedinto a vessel (e.g., artery) of a patient in order to measure thepressure at certain locations along the vessel, which is underinvestigation.

One problem with pressure guide wire 100 is that the individualelectrical contacts are very difficult and expensive to integrate intothe guide wire. Contacts 104 are individual metal bands, which areseparated by non-electrically conductive spacers 116. Duringmanufacture, each of the individual contacts 104 have to be soldered tothe appropriate electrical conductor (not shown, e.g., electrical wire),which is attached to pressure sensor 110.

After the appropriate electrical conductor is soldered or welded to itscorresponding contact 104, each individual contact has to be adhesivelybonded to the rest of the guide wire 100. The spacers 116 also have tobe individually inserted and bonded to the adjacent contact(s) 104. Thebonding of the spacers 116 and contacts 104 causes further problems inthat the adhesive which bonds them together tends to seep between thejoints and has to be removed from the exterior portions of the proximalend of the guide wire 100. Given the small size of the guide wire 100,all of these time consuming steps have to be performed by assemblyworkers using microscopes which further increase the opportunity formanufacturing mistakes to occur.

Problems can also occur with the contacts 104 or spacers 116 becomingseparated from the rest of the assembly due to bad bonding of aparticular contact 104 or spacer 116. Another manufacturing problemoccurs with the solder joints, which interconnect the electricalconductors coming from pressure sensor 110 to the individual contacts104. Given that the electrical conductors have to be soldered to theinside surface of the contacts 104, there is very little room in whichto solder the contact with a soldering tool, thus some bad solder jointscan occur during production.

A need thus exists in the art for a contact assembly, which can overcomethe problems associated with the prior art mentioned above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a prior art pressure guide wire.

FIG. 2 shows a prior art connector that interconnects the guide wire ofFIG. 1 to a monitoring apparatus.

FIG. 3 shows an electrical connector in accordance with the preferredembodiment of the invention before it is rolled-up into a substantiallycylindrical shape.

FIG. 4 shows the electrical connector of FIG. 3 interconnected to apleurality of electrical conductors in accordance with the invention.

FIG. 5 shows the assembly of FIG. 4 in a rolled-up form.

FIG. 6 shows the rolled-up assembly of FIG. 5 mounted to a portion of acore wire.

FIG. 7 shows the assembly of FIG. 6 with a shaft attached to theelectrical connector in accordance with the invention.

FIG. 8 shows a cross-sectional view of FIG. 7.

FIG. 9 shows an alternate embodiment of the electrical connector.

FIG. 10 shows a pressure guide wire in accordance with the invention.

FIG. 11 shows an alternative embodiment in which a tubular substrate isused to form the electrical connector.

FIG. 12 shows the tubular member of FIG. 11 after metallization of itsouter surface.

FIG. 13 shows the tubular member of FIG. 12 after it has been cut andoverlapped.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now to the drawings and in particular to FIG. 3, there isshown a circuit carrier (substrate) such as a substantially cylindricalelectrical connector 300 comprising substrate 302 and three electricallyconductive bands 304, 306 and 308. The electrical connector 300 is thepreferred embodiment is formed from a “flex” circuit or flex circuitboard 302 which is preferably manufactured from a polymide such asKAPTON™ manufactured by Dupont, Inc., or other flexible materials usedin the art. The thickness of substrate 302 should be such that it can bere-shaped in a relatively tight radius of curvature. The flex circuitcould, for example, be of the order of 25 um thick, or less.

The flexible substrate 302 preferably includes an extension portion 310,which provides termination points for parallel runners 312, 314 and 316which are interconnected to bands 304, 306 and 308. Runners 312, 314 and316 have a pitch in the order of 0.002 to 0.004 inch. This pitch isrequired in order to interface the circuit to the group of electricalwires that travel along the length of the flexible elongate member tothe electrical device (e.g., pressure sensor, etc.). Since the guidewire has a small cross-sectional diameter, the wires have to be small,and are therefore close together. Ideally, the pitch of the runners 312,314 and 316 matches the pitch of the wires so that when the wires arebonded to the flex circuit, there is no need to spread the wires, andthe assembly fits within the profile of the flexible elongate member.The wires may be stripped of insulation and attached with conventionalmeans such as soldering or welding.

In FIG. 4 the flexible circuit board 300 is shown attached to threeelectrical conductors 402 in the form of a cable also known as atrifilar. Each of the bands has a corresponding electrical conductorthat is attached by soldering, welding or by another well-knownattachment technique.

In FIG. 5 the assembly of FIG. 4 is shown folded in substantiallycylindrical fashion with ends 502, 504 of the flexible circuit board 300being slightly overlapped in order to pass over the runners 312, 314 and316. The overlapping maintains the bands 304, 306 and 308 in alignment.The ends of the flexible circuit board are then bonded using any one ofa number of conventional adhesives in order for the electrical connector300 to remain in its substantially cylindrical state. Once bonded, themetallization bands 304, 306 and 308 form three parallel cylindricalbands that run around the periphery of the connector 300. Alternatively,in other designs, the bands 304, 306 and 308 do not have to run aroundthe entire periphery of connector 300.

In FIG. 6, the electrical connector 300 and cable 402 are shown mountedto a core wire 602 (only a portion shown) which forms the backbone forthe pressure guide wire 100. The electrical connector 300 is attached acertain distance 604 from the proximal end 606 of core wire 602. Theflexible circuit 300 is filled with adhesive between core wire 602 andinner surface of the flexible circuit board 300 in order to fix andstiffen the electrical connector 300.

In FIG. 7 the partial guide wire assembly of FIG. 6 is shown with ashaft or hypotube 704 (similar to shaft 106) attached to the electricalconnector 300. The electrical connector 300 can be attached to hypotube704 using one of a number of adhesives such as a polyurethane andoligomer mixture. An optional window 702 is provided in hypotube 704,which could allow for the soldering of insulated electrical conductors402 after the hypotube and electrical connector 300 have been mated. Ifoptional window 702 is utilized, it is aligned with (also referred to asbeing in substantial registration with) extension portion 310 found inthe substrate 302. Once the electrical conductors 402 are soldered on tothe electrical connector 300 in the window 702 is covered withinsulative “fill” adhesive such as epoxy. A cross-sectional view takenalong line 8-8 is shown in FIG. 8. The electrical connector 300 isattached to core wire 602 using a nonconductive adhesive such as epoxy802. The epoxy not only serves to attach the flexible circuit board tocore wire 602 it is also provides a backing material which helps stiffenthe flexible circuit board used in this embodiment. The area between thecore wire 602 and inner surface of electrical connector 300 ispreferably filled with adhesive or other filler in order to stiffen theelectrical connector 300.

An alternate embodiment of the electrical connector of the presentinvention is shown in FIG. 9. Instead of overlapping the ends of theflexible substrate 302 as shown in FIG. 5, the end portions 901 and 902of the flexible substrate 302 are bonded substantially flush to eachother using adhesive. There is no need to overlap the ends of theflexible substrate in this embodiment as compared to the one-sidedembodiment shown in FIG. 5 because in this embodiment the flexiblesubstrate 302 is a two-sided circuit board design. Conductive bands 914are located on a first surface 910 and corresponding runners 906 arelocated on a second surface 912. The bands 914 and runners 906 areinterconnected using pass-through vias 904.

In FIG. 10 there is shown a pressure guide wire 1000 in accordance withthe present invention. Instead of using several individual conductivebands 104 and insulative spacers 116, the pressure guide wire 1000 usesthe electrical connector 300 of the present invention. By using theelectrical connector 300 of the present invention the time tomanufacture the pressure guide wire 1000 is reduced. Also, the problemwith the individual bands 104 and spacers 116 becoming detached from therest of the pressure guide wire assembly as found with the prior artguide wire 100 are eliminated.

In an alternate embodiment of the present invention, a tubular member orsubstrate 1100 is used as the starting point in place of a flexible flatsubstrate 302 as shown in FIG. 3. Preferably, tubular member 1100includes an extension portion 1102 similar to extension portion 310. InFIG. 12 cylindrical bands 1202, 1204, 1206 and runners 1208, 1210 and1212 are added using a conventional metallization technique such assputtering. Other well-known metallization techniques can be used toattach the metallization to the outside surface of electrical connector1200.

A non-metallized area 1214 is left along the length of the tubularmember. The non-metallized area is the area in which the tubular memberis cut along its entire length. Once cut, the ends of the tubular memberare overlapped in order to cross over the three runners 108, 1210 and1212. Once overlapped as shown in FIG. 13, the outside surface offlexible connector includes three substantially cylindrical metal bands1202, 1204 and 1206. The overlapped ends are bonded together so theoverlapped stated is fixed.

An electrical connector cable 1302 is attached to the runners 1208, 1210and 1212 at extension 1102. Tubular member 1100 can be formed from anumber of materials, which are amenable to metallization such as apolymide tube. Although the embodiment shown in FIG. 3 requires aflexible circuit substrate since the starting point is a flat substrate,tubular member 1100 can be formed from semi-stiff or stiffer materialsif so desired since the member is already in a substantial cylindricalstate prior to metallization of its outer surface.

The present invention accomplishes a completely new way of forming anelectrical connector on a flexible elongate member such as acardiovascular guide wire 1000. The invention accomplishes this with asingle member that forms the multiple connection requirements. Thesimplicity of the design also enables rapid and effective assemblytechniques, and is compatible with automatic processes that can beperformed by machines. The component cost is also reduced compared tothe prior art.

The single substrate design can be mass produced using standardphoto-lithographic techniques in the case where the flat substrate 302is used, and standard metallization techniques such as sputtering in thecase where the tubular substrate 1100 is utilized as the starting point.The present invention also eliminates a number of previously complicatedassembly steps. In addition, the invention allows the electrical device(e.g., pressure sensor, flow sensor, etc.) and electrical conductor 300to be attached and tested prior to completion of the guide wire 1000.

While the intention has been described in conjunction with specificembodiments, it is evident that many alternatives, modifications,permutations and variations will become apparent to those skilled in theart in light of the foregoing description. For example, although in thepresent invention the preferred embodiment has been described as apressure guide wire, other flexible elongate members such as those usedto diagnose or treat coronary vascular areas can take advantage of thepresent invention.

1. A method for making a flexible elongate member for insertion into humans or animals, the method comprising the steps of: first forming a flexible member having proximal and distal ends; second forming a circuit carrier comprising a substantially cylindrical electrical connector with at least one conductive band, the electrical connector having a first end portion that is flush with a second end portion; first attaching an electrical device in proximity to the distal end of the flexible member; interconnecting an electrical conductor to the electrical device; third forming an electrically conductive bond between the electrical conductor and a conductive path on the circuit carrier comprising the at least one conductive band; and second attaching the substantially cylindrical electrical connector in proximity to the proximal end of the flexible member.
 2. A method as defined in claim 1, wherein the circuit carrier is formed comprising the steps of: providing a substantially flat substrate with the at least one conductive band, the substantially flat substrate having a first end portion and the second end portion; reshaping the first end portion so that it is flush with the second end portion forming the substantially cylindrical electrical connector with the conductive band on its outer surface; and bonding the first end portion and the second end portion in the area where the first end portion is flush with the second end portion.
 3. A method as defined in claim 1, wherein the electrical device is a sensor and the flexible elongate member forms a guide wire.
 4. A method as defined in claim 1, wherein the electrical device is a flow sensor and the flexible elongate member forms a flow guide wire.
 5. A method as defined in claim 1, wherein the electrical device is an ultrasonic transducer and the flexible elongate member forms an intravascular ultrasound guide wire.
 6. A method as defined in claim 1, wherein the circuit carrier is formed comprising the steps of: forming a tubular member having an outer surface; and forming the at least one conductive band on the outer surface of the tubular member such that the tubular member and the at least one conductive band form the substantially cylindrical electrical connector.
 7. A method as defined in claim 1, further comprising the steps of: forming an extension portion on the circuit carrier; electrically connecting the electrical conductor to the at least one conductive band such that the electrically conductive bond is formed on the extension portion of the circuit carrier.
 8. A method for making a cardiovascular guide wire, the method comprising the steps of: first forming a core wire having a proximal and distal end; second forming a circuit carrier comprising a substantially cylindrical electrical connector with at least one conductive band; the electrical connector having a first end portion that is flush with a second end portion; first attaching an electrical device in proximity to the distal end of the core wire; interconnecting an electrical conductor to the electrical device; third forming an electrically conductive bond between the electrical conductor and a conductive path on the circuit carrier comprising the at least one conductive band; and second attaching the substantially cylindrical electrical connector in proximity to the proximal end of the core wire.
 9. A method as defined in claim 8, wherein the circuit carrier is formed comprising the steps of: providing a substantially flat substrate with the at least one conductive band, the substantially flat substrate having a first end portion and the second end portion; reshaping the first end portion so that it is flush with the second end portion forming the substantially cylindrical electrical connector with the conductive band on its outer surface; and bonding the first end portion and the second end portion in the area where the first end portion is flush with the second end portion.
 10. A method as defined in claim 8, wherein the circuit carrier is formed comprising the steps of: providing a substantially flat substrate with the at least one conductive band, the substantially flat substrate having a first end portion and a second end portion; reshaping the first end portion so that it is flush with the second end portion forming the substantially cylindrical electrical connector with the conductive band on its outer surface; and bonding the first end portion to the second end portion.
 11. A method as defined in claim 8, wherein the circuit carrier is formed comprising the steps of: forming a tubular member having an outer surface; and forming the at least one conductive band on the outer surface of the tubular member such that the tubular member and the at least one conductive band form the substantially cylindrical electrical connector.
 12. A method as defined in claim 8 wherein the guide wire further comprises a hypotube and further comprising the steps of running the electrical conductor inside the hypotube and coupling the hypotube to the substantially cylindrical electrical connector.
 13. A method as defined in claim 12, wherein the hypotube further includes a window and the substantially cylindrical connector includes an extension portion, further comprising the steps of: forming the electrical bond connection between the electrical conductor and the at least one conductive band on the extension portion; and bringing the hypotube and the substantially cylindrical electrical connector together with the window and the extension portion in substantial registration prior to coupling the substantially cylindrical electrical connector and the hypotube.
 14. A method as defined in claim 8, wherein the electrical device is a pressure sensor.
 15. A method as defined in claim 8, wherein the electrical device is a blood flow sensor.
 16. A method as defined in claim 8, wherein the electrical device is an ultrasound transducer.
 17. A method as defined in claim 2, wherein the electrical device is a sensor and the flexible elongate member forms a guide wire.
 18. A method as defined in claim 2, wherein the electrical device is a flow sensor and the flexible elongate member forms a flow guide wire.
 19. A method as defined in claim 2, wherein the electrical device is an ultrasonic transducer and the flexible elongate member forms an intravascular ultrasound guide wire.
 20. A method as defined in claim 2, further comprising the steps of: forming an extension portion on the circuit carrier; electrically connecting the electrical conductor to the at least one conductive band such that the electrically conductive bond is formed on the extension portion of the circuit carrier. 